EFFECTS OF PRETREATMENT ON BIOBUTANOL YIELDS FROM RICE-BRAN AND DEOILED RICE-BRAN PROCESSED WITH Clostridium saccharoperbutylacetonicum N1-4
Acid and enzymatic pre-treatment of selected lignocellulosic materials [Rice Bran (RB) and Deoiled Rice Bran (DRB)] were conducted to facilitate the release of simple sugars for fermentation process leading to biofuel production. In this study, an innovative approach involving the use of acids to breakdown the complex lingo-cellulosic structure of RB and DRB was utilised. In addition, RB and DRB samples were subjected to physical (heat treatment) and enzymatic treatments, sequentially; in order to improve the amount of simple sugar available as substrate in a microorganism assisted fermentation process. The released sugar from the various treatment regimes were subjected to fermentation process. The highest total fermentable sugar obtained from the Trichloroacetic Acid (TCA), HCl and H2SO4 treated hydrolysate were 33.07 g L-1, 27.14 g L-1 and 31.93 g L-1 for treated hydrolysates, respectively. DRB samples showed a higher total sugar yields and fermentation products than RB samples. The highest butanol yield obtained from the TCA, HCl and H2SO4 treated hydrolysate were 8.66 g L-1, 5.32 g L -1 and 7.86 g L-1, respectively, after fermentation. The Acetone-Butanol-Ethanol (ABE) yield and productivity of the TCA, HCl and H2SO4 treated DRB hydrolysates were 0.47 g/g and 0.1g L-1 h-1, 0.32g/g, and 0.07 g L-1 h-1 as well as 0.42 g/g, and 0.08 g L-1 h-1, respectively. (This is consistent with Table 1) The high ABE yield and productivity values suggest that TCA is a good novel pre-treatment agent for biomass fermentation.